Composition profiling of a SiGe island. (a) Experimental (black) and reconstructed (red) Raman spectra. The blue spectra are the weighted ϕx components. (b) Relative spectral contributions, ax, with respect to the composition. (c) Composition profile inside each island modeled as a multilayer. The distance from the substrate surface is z. The uncertainty on the thickness values by Raman spectroscopy is about 10% of the total thickness. The data are compared to AFM and X-ray  results of similar islands. In the inset of panel (c), the AFM profile of one island is reported.
Picco et al. Nanoscale Research Letters 2012 7:633 doi:10.1186/1556-276X-7-633